Fuse cutout



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JNVENTORS James M.Wolloce and Earl F. Beach q BY 1/ o ATTORNEY FUSE CUTOUT Filed May 7, 1949 F ig.l.

J- M. WALLACE ETAL Insulation June 30, 1953 KVigNESSES: WM

Patented June 30, 1953 UNITED STATES PATENT OFFKIE FUSE CUTOUT Application May 7, 1949, Serial No. 91,934

19 Claims. 1

This invention relates to electrical protective devices and more especially to circuit interrupters of the open fuse type for outdoor use.

An outstanding general object of this invention is the provision of a simple and reliable cutout or interrupter of the open fuse type which is well suited for arresting the flow of excess current in an electrical transmission line.

Another object of this invention is that of providing an open fuse circuit interrupter for outdoor use and having features which assure effective interruption of the related circuit when the device is exposed to excess current.

A further object of this invention is that of providing an inexpensive and reliable open fuse electrical cutout which is easily produced and installed to circuit protective position, and which is thoroughly capable of enduring exposure to widely varying outdoor weather conditions or the like and of retaining the ability to function in a satisfactory manner under these conditions.

Another object of the present invention is that of providing a simple, compact open fuse cutout assembly for an outdoor transmission line, which cutout device is so protected against rain, ice, sleet, and snow as to retain properties for protecting the line.

The present invention is of especial importance where applied to the problem of outdoor transmission of electrical energy and to the provision of fuse cutouts such as may be used on line towres, poles, transformers, or the like, as safety devices in a power transmitting system. In this connection it will be appreciated that open type fuse cutouts are effective for arresting the flow of current by spending a fusible electrically conductive or heat sensitive portion in response to overload current and thereupon opening the line with a snap action.

There are certain heretofore known open fuse cutouts or circuit protective devices which have been eliminated from possible use by virtue of such considerations as the cost of production, and the expense of installation and maintenance in the power supply line. More specifically, some of these devices have been objectionable from the standpoint of consisting of too many Working parts for practical production of operation, the requirement of an objectionable amount of space by these parts when assembled, extreme susceptibility to mechanical failure in use, and excessive cost from the standpoint of replacement or repair once put into operation.

A great variety of open fuse cutouts in the prior art, while depending upon fusion of a 2 fusible element in response to overload, are 01 such structural arrangement as to be rendered inoperative by ice and snow against effecting the snap action after fusion occurs. The failure thus to snap often leads to the development of that the failure of these cutouts to achieve reliable automatic operation defeats their purpose and calls for continued surveillance and maintenance to compensate for the inherent faults of their construction. It will also be appreciated that a great number of the heretofore known open fuse circuit interrupters while being susceptible to failure of operation under damp freezing weather conditions, are of an extremely complicated mechanical nature. These devices usually have certain highly critical components, necessary for the provision of the snap action, fully exposed to the weather so as to freeze and remain inert although released for snap action. It is during this time that arcing so often becomes a hazard, as for example, due to the proximity of the fusion-separated ends of the power line and the inability of the snap action to occur and separate these ends by a safe distance.

A further object of this invention, accordingly, is the provision of a practical and durable open fuse circuit interrupter for cold or warm weather outdoor use in which the fuse promptly melts or softens in response to overload current and the melting or softening is reliably followed by a snap action for thoroughly separating the circuit leads of the fuse.

A still further object of this invention is the provision of a practical and mechanically simple snap acting open fuse cutout, compactly and effectively shielded against the effects of ice and snow.

The preceding objects and other objects of this invention will become more apparent upon consideration of the following description of a preferred embodiment thereof, when taken in connection with the attached drawing, in which:

Figure 1 represents, in side elevation, an open fuse cutout made in accordance with the invention;

Figure 2 is a, plan View depicting details of the top portion of the device in Figure l, but with fuse links omitted; and

Figure 3 is a fragmentary view, in plan, of the under side of the apparatus in Figure 1.

In the particular embodiment of the invention disclosed in the accompanying drawing, there is provided an open fuse cutout Ill which includes an electrical insulator l I, contact arms 12 and l3, and a fuse link I l interconnecting these arms. The arms l2 and 13 are biased for relative movement so as to effect separation one from the other under conditions of overload current flow between electrical terminals l6 and ll of the insulator ll. A bracket 35 illustratively serves for mounting the insulator in an upright position as on a pole, line tower or transformer casmg.

The insulator ll preferably is oblong in the upright direction, and conveniently is round or substantially circular in transverse section. It is made of porcelain, glass, or of any other suitable dielectric. Where, for example, the cutout i0 is to be used for lending safety to a high voltage transmission line, as is often the case, a considerable advantage is had by employing an insulator l I having a corrugated surface, such as provided by a series of raised annular skirt portions Ila spaced outside along the length thereof. This corrugated surface is illustratively achieved by molding the insulator to the desired integral form inclusive of the corrugations, such as by pouring glass into a mold of sufficient proportions to produce the entire insulator unit as a molded product. The corrugated surface tends to arrest corona discharge and prevent leakage currents under conditions of excess moisture between the terminals It and 11.

To assist in the avoidance of a free electrical discharge path over the surface of the insulator ll, the bottom surface of at least some of the raised annular portions Ila preferably is substantially normal to the longitudinal axis of the insulator or is inclined in an upward direction from the rim of the corresponding annular por tion. The top surface of at least some of the raised annular portions lla advantageously slopes downward and outward from a sheltered position beneath the underneath surface of the annular portion lla next above, thus being protected against moisture, sleet, ice, rain, or the like, and against corona discharge. The mounting bracket 35 conveniently includes a substantially U-shaped strip or band which advantageously passes around the insulator l I at a point intermediate the plurality of raised annular portions He. The raised annular portions thus afford protection against electrical discharge to the bracket 35. A bolt 35a, having a corresponding nut, conveniently extends through opposed openings in the strip legs of the U-shaped bracket 35 for drawing the latter to frictional engagement transversely around the insulator l I.

A bottom portion [lb of the insulator ll is reentrant in shape, as by having a skirt, giving a recess l8 of suincient size to receive and protect a spring 20 from the effects of moisture, rain, ice, sleet or snow. This arrangement not only assures thorough and highly satisfactory protection for the spring, but contributes to compactness, and ease of production of the cutout ID.

The bottom portion llb advantageously is a lowermost extension of the insulator ll, integral with the same and in axial alignment with the raised annular portions Ila. The portion llb, and more particularly the top surface thereof, illustratively begins beneath the adjacent lower surface of the overlying raised annular portion lla so as to be shielded and consquently avoid moisture by the latter against corona discharge. In this, the surface of the bottom portion llb preferably extends down and out, as on a curve, and in the manner of a dome, from a marginal position relative to the rim of the adjacent raised annular portion Ma, and thence has a substantially cylindrical outside surface and is re-entrant from the underneath, affording an axial bore, and thus the recess [8.

In the present embodiment, the bottom portion lib of the insulator supports the lower terminal It. This terminal illustratively comprises a band 2! of strip material which, for example, rests transversely of the insulator II in a groove lie, the latter being formed in the outside of the cylindrical wall of bottom portion l lb. Free ends of this band are turned out to provide substantially parallel ears 22 and 23, in which aligned openings accommodate a bolt 24 for tightening the band to frictional engagement with the insulator ll. Extending from the band 2|, as from the ear 22, and conveniently integral therewith, is a clamp 25, as of a resilient clip type, for holding one end of an electrical conductor. Likewise, terminal I! disposed at the top of the insulator ll affords a clamp 28, illustratively of a resilient clip type, for electrically connecting another conductor to the cutout ll]. The terminal l'l conveniently is secured to the contact arm l3 in a manner to be described. Both line terminals l6 and ll of the cutout ll], of course, are made of electrically conducting material such as copper or a copper alloy, the latter, for example, being a cobalt-beryllium-copper composition. If desired, the terminal l6 may be directly mounted on the contact arm l2 for movement with the same instead of being fixed to the insulator ll. Under these circumstances, the Wall of insulator ll conveniently affords a bearing for the pivot pin 3| to enable the pivoting action of arm l2.

A top zone of the insulator l I, preferably hav ing a substantially cylindrical portion ll 1' inset from the rim of the uppermost raised annular portion Ha and in axial alignment therewith, is conveniently headed off by an annular lip or head He. With this arrangement the top of the insulator ll affords attachment space for the contact arm l3, which arm now will be more fully described.

The contact arm l3 advantageously includes an electrically conductive strip as, for example, of copper alloy or copper-clad steel, which in the vicinity of mid-length illustratively is bent to a semi-circle |3(Z as on a radius substantially conforming to the curvature of the insulator portion H1. The semi-circular portion [3a passes around the insulator portion Hi, there acting as a friction band retained between lip or head I le and the adjacent raised annular portion Ila of the insulator l l. Serving as extensions of the semi-circular portion of the contact arm l3a are substantially parallel straight portions l3b reaching laterally away from the insulator ll and held spaced by a strut I30, the latter, for example, being welded in position. Beyond the strut, and in a direction going away from the insulator ll, the contact arm l3 comprises extensions lSd which preferably are continuations of the strip material of the circular portion [3a and substantially straight portions I31) but are inclined toward each other and finally merge at an apex and into abutting portions I3e, the latter being fastened together as by welding. Along the lengths of portions l3b, are opposed openings through which a bolt 29 extends. This bolt, with the aid of nut 30, serves to pull the contact arm portions I31) together between the insulator II and the strut I30 and thus tightens the semi-circular portion l3a to firm-frictional engagement against the surface of the insulator portion Hf, and also maysecure terminal H to contact arm I3. The contact arm l3 thus preferably takes the form of a rigid truss in which the strip portions extend from a relatively fixed relation on opposite sides of theinsulator ll out to give an apex and a mutual bracing effect. The truss is reinforced against vertical movement relative to insulator ll because of resistance to bending afforded by the strip, the strip material being disposed so that in transverse cross-section the long dimension is substantially vertical. Also, the contact arm resists lateral deflection by reason of the bends and angularity of the strip and with the aid of strut I30.

At the outer end of the contact arm l3 and, for example, fastened to portions I3e, are blades I3;f, these extending back upon the contact arm portions I3d and forming jaws therewith for resiliently receiving and holding the upper end of fuse link I4. To facilitate insertion of the fuse link, the blades I31 are bent, gradually turning away at their free ends from the underlying contact arm portions l3d, as on a circular curve. The outermost ends of blades I31 conveniently extend beyond the contact arm portions I3e and terminate in curved ends which are concave toward and confronting one another as shown in the accompanying drawing. This not only results in an ornamental configuration,

but eliminates sharp corners to avoid corona discharge. Usually, these blades are made of electrically conductive metal such as a resilient copper alloy or copper-clad steel.

Lower contact arm I2 of the open fuse cutout I0 is rotatably mounted, this mounting including a round electrically conductive pin 3|, as of cobalt-beryllium-copper alloy, extending through clearance holes in the bottom portion [lb of insulator II and through aligned openings or bearings in the lower terminal band 2|. The ends of the round pin 3|, are reduced, somewhat outside the lower terminal band, to square or other suitable configuration and receive corresponding ends of electrically conductive strips 12a having shaped holes for conforming to the shaped pin ends and locking the pin and the members IZa together for unitary rotation. These shaped ends of the pin conveniently are upset over the outside surface of members l2a thus preventing the several elements from being pulled apart. The pin 3| is usually restrained against longitudinal sliding movement such as by the spring 20, or by suitable stops (not shown) fixed to the pin and loosely bearing against the insulator wall surface of recess I8, so as not to arrest pivotal movement of the contact arm I2. The shaped ends of the pin 3| advantageously reach beyond the outside surface of the insulator II and hold the strips I2a to be substantially clear of the insulator wall. Thus, any ice which may accumulate on the pivot arm I2 tends to crack off under torque applied to the pin without impairing pivotal movement of arm I2.

The strips I2a of the contact arm I2, in extending away from pin 3|, preferably are straight and disposed in substantially parallel relation for a distance laterally out from the insulator I I, thereafter are angled and gradually approach each other in a straight line to an apex and then are angled back to substantially parallel abutting relation for a suitable distance at the outer ends l2e similar to portions I3e of contact arm I3. The abutting outer ends I2e are suitably fixed together as by welding, thus forming a rigid frame comprising the members I2a and pin 3|. Strips I2a afford further rigidity by having the long dimension of their transverse crosssection substantially vertical.

Fastened to the abutting ends I2e of the members IZa, as by welding, are blades I21, conveniently constructed and arranged in the same manner as blades I31 of contact arm l3. The blades I21 extend back over the respective members In and form jaws with the samefor receiving and clamping the lower end of fuse link I4. Members I2a and blades I2f conveniently are made of the same materials as the corresponding portions in upper contact arm l3.

The spring 20 illustratively is of the torsion variety and passes around pin 3i within the confines of recess I8 for added compactness. One end of this spring comprises a hook 25a (see Fig. 3) which engages a catch 3 la extending laterally from the pin and rotatable with the same. The other end of the spring 29 is loose on the pin 3! and has (see Fig. 1) an extension 20b contacting the inside wall of recess l8 so as to arrest rotation of this end of the spring when the contact arm I2, including pin 3|, is rotated in a counterclockwise direction in Figure 1. With the counterclockwise rotation of the pin 3 I, catch em turns the torsion spring 29 to a tighter position by engagement with the hook 280/... This tighter winding serves to bias the contact arm l2 in favor of clockwise rotation, as viewed in Figure 1. If desired, the spring 20 during assembly of the cutout Ill may be mounted in a partially wound condition with the contact arm I2 in lower clockwise position as represented by dotted lines in Figure 1. I This gives a stronger biasing action in favor of clockwise rotation of arm l2 when the latter is turned counterclockwise to the full line position in Figure 1.

Fuse link I4 preferably includes an opposed pair of electrical conductors 32, made for example of copper Wire, and which are provided at their outer ends with eyes 33. On these eyes and located immediately adjacent to the inner sides thereof at the point of 'junction with the conductors 32, are buttons or stops 33a for pressing against the outside surfaces of contact arms I2 and I3. The inner end portions of the electrical conductors 32 are spaced apart to form a gap and located in this gap and connected to the conductors 3'2 is a fusible element 3c of relatively low melting point material. The fusible element 34 and the inner ends of the conductors 32 preferably are enclosed within a tube 36 made, for example, of a weather protective compound such as phenolic resin and lined with fiber capable of emitting an arc-suppressing gas upon rupture of the fusible element 35 due to overload current.

In the use of the cutout I0 disclosed herein, one of the opposed electrical conductors 32 of the fusible link It is drawn into position between one of the blades I2 and the corresponding member IZcL of contact arm I2 with the aid of a suitable tool. For this purpose, a conventional hook stick is useful for exerting a pull upon an appropriate one of the eyes 33. With further use of the tool, the conductor 32 at the opposite end of link I4 is then drawn between one of the blades I31 and the corresponding member [3d of contact arm I3. In this latter operation, contact arm [2 is pulled up and rotated in a counterclockwise direction against the bias of spring 20, the link [4 once in operative position being sufficiently short in length to have stops 33d bear upon the outer edges of contact arm 12 and I3 and retain the arm l2 in the up position. Then with normal current conditions prevailing, the open fuse cutout It! serves to maintain current flow through the circuit, of which terminal It inclusive of band 2|, pin 3|, contact arm 12, fusible link l4, contact arm l3 and terminal ll comprise a part. If, however, overload currents prevail through the electrically conductive elemerits just named, the fusible element 34 in the link 14 ruptures. When that occurs, contact arm l2 snaps down in a clockwise direction, quickly pulling apart the electrical conductors of line Hi, this action being urged by the biasing spring 20. Current flow thus no longer prevails across the cutout II], but can be restored, if safe transmission limits exist, by introducing another link [4 having a fusible element 34 of appropriate current rating.

Thus, it will be seen that in this invention there is provided an open fuse cutout in which the various objects noted herein, together with many thoroughly practical advantages are successfully achieved. It will be seen that the cutout is simple and is effectivel biased in favor of snapping to open circuit position upon overload currents being encountered. Also it will be seen that the biasing means and the related structure are reliably protected against the effects of Weather and particularly moisture and freezing which otherwise might impair the biasing action, and thus the cutout is well suited for outdoor use. Further, it will be noted that the shielding arrangement provided for the biasing means contributes to simplicity and compactness of the safety device.

We claim as our invention:

1.A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and being re-entrant the base thus providing a recess therein, a transmission line terminal mounted adjacent the upper end of the insulator, an upper contact arm fixedly mounted on the upper end of said insulator and electrically connected to said transmission line terminal, another transmission line terminal mounted adjacent the lower end of the insulator, a lower contact arm pivotally mounted at the lower end of said insulator and electrically connected to said other transmission line terminal, a fuse link interconnecting said contact arms, and spring means within the recess of said in-- sulator for protection against weather and for biasing said pivotally mounted contact arm away from said fixedly mounted contact arm to tension said fuse link.

2. A. fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bot tom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted on the upper end of said insulator and electrically connected tosaid transmission line terminal, another transmission line terminal mounted adjacent the lower end of the insulator, a rigid contact arm including pivot means extending through said skirt of the insulator into said recess and electrically connected to said other transmission line terminal, a fuse link interconnecting said contact arms, and spring means within said recess of the insulator for protection against weather and for urging said pivot means to rotate the second said contact arm away from the first said fixedly mounted rigid contact arm and thus tension said fuse link.

3. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a contact arm fixedly mounted on the upper end of said insulator, a transmission line terminal including an electrically conductive band around said skirt, a contact arm including pivot means extending into said recess through aligned openings in the band of said transmission line terminal and the insulator skirt, a fuse link interconnecting said contact arms, and spring means within said recess of the insulator for protection against weather and for urging said pivot means to rotate the related contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

i. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an. upright position and having a skirt giving a recess in the underneath side of the insulator bottom and having a plurality of raised portions upward of the skirt for shielding the same and one another against corona discharge, a rigid contact arm fixedly mounted on the upper end of said insulator above said raised portions thereof, a transmission line terminal including an electrically conductive band around said skirt, a rigid contact arm including pivot means extending into said recess through aligned openings in the band of said transmission line terminal and the insulator skirt, a fuse link interconnecting said rigid contact arms, and spring means within said recess of the insulator for protection against weather and for urging said pivot means to rotate the related rigid contact arm away from said fixedly mounted rigid contact arm and thus tension said fuse link.

5. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a contact arm, fixedly mounted on the upper end of said insulator, a transmission line terminal including an electrically conductive band clamped laterally around said skirt, a lower contact arm including an electrically conductive pivot pin extending into said recess through aligned openings in the band of said transmission line terminal and the insulator skirt with reduced shaped ends substantially clear of the outside surface of the skirt wall, and said contact armv including electrically conductive means having shaped openings fitting over said shaped ends of the pin so as to rotate in interlocked relation withv the same, a fuse link interconnecting said contact arms, and torsion spring means within said recess of the insulator for protection against weather and for urging said pivot pin to rotate the related contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

6. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted on the upper end of said insulator and electrically connected to said transmission line terminal, another transmission line terminal mounted adjacent the lower end of the insulator, a lower rigid contact arm including a pivot pin extending through aligned openings in the wall of said skirt and through said recess in the insulator bottom end, said lower rigid contact arm being electrically connected to said other transmission line terminal, a fuse link interconnecting said contact arms externally of said insulator, and spring means within said recess of the insulator for protection against weather and for urging said pivot pin to rotate the lower contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

'7. A fuse for outdoor use comprising, an electrical insulator having a recessed base and a plurality of raised portions upward of the base for shielding the same and one another against corona discharge, a bracket for mounting said insulator in an upright position and having a band around and frictionally engaging the body of the latter intermediate said plurality of raised portions thereof, a contact arm fixedly mounted on the upper end of said insulator above said raised portions, a transmission line terminal including an electrically conductive band around said recessed base below said raised portions, a contact arm including pivot means extending into the recess of said base through aligned openings in said transmission line terminal band and insulator, a fuse link interconnecting the said contact arms, and spring means within said recess of the insulator for protection against weather and for engaging said pivot means to rotate the related contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

8. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position, an upper contact arm mounted on the upper end of said insulator and a lower contact arm pivotally mounted at the lower end of said insulator, each of said contact arms including spaced strip portions extending from fixed positions adjacent said insulator out to give an apex for mutual bracing and having the long dimension of their transverse cross-section substantially vertical, a fuse link interconnecting the outer ends of said contact arms, and spring means for biasing said pivotally mounted contact arm away from said fixedly mounted contact arm to tension said fuse link.

9. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position, a rigid upper contact arm mounted on the upper end of said insulator, a lower contact arm including a pivot pin supported on said insulator, said lower contact arm including strip portions respectively fixed to the opposite ends of said pivot pin for rotation with the latter and reaching out to give an apex for mutual bracing with the long dimension oftheir transverse cross-section substantially vertical, a fuse link interconnecting the outer ends of said contact arms, and spring means for biasing said lower contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

10. A fuse cutout for outdoor usecomprising, an electrical insulator suited for mounting in an upright position, an upper contact arm fixedly mounted on the upper end of said insulator and a lower contact arm pivotally mounted at the lower end of said insulator, each of said contact arms including spaced strip portions extending from fixed points adjacent said insulator out to an apex for mutual bracing and having the long dimension of their transverse cross-section substantially vertical, a fuse link, resilient jaws cooperating with the outer end of at least one of said strips of each contact arm for holding said fuse link to interconnecting position therebetween, and spring means for biasing said lower contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

11. A fuse cutout for outdoor use comprising, an electrical insulator having a recessed base and a plurality of raised portions upward of the base for shielding the same and one another against corona discharge, a bracket for mounting said insulator in an upright position and having a band around and frictionally engaging the body of the latter intermediate the plurality of raised portions thereof, a rigid upper contact arm mounted on the upper end of said insulator above said raised portions, a line terminal in cluding an electrically conductive band around said recessed base of the insulator, a lower contact arm including a pivot pin extending laterally through said insulator base and across said recess therein, through aligned openings in the band of said transmission line terminal and the insulator wall, and. said lower contact arm ineluding strip portions respectively fixed to the opposite ends of said pivot pin for rotation with the latter and reaching out to give an apex for mutual bracing with the long dimension of their transverse cross section substantially vertical, a fuse link interconnecting the outer ends of said contact arms, and torsion spring means within the recess of the base of said insulator for protection against weather and for biasing said pivotally mounted contact arm away from said fixedly mounted contact arm to tension said fuse link. 7

12. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position, an upper contact arm fixedly mounted on the upper end of said insulator and a lower contact arm pivotally mounted at the lower end of said insulator, each of said contact arms including spaced strip portions extending from fixed points adjacent said insulator out to an apex for mutual bracing and having the long dimension of their transverse cross-section substantially vertical, a fuse link, resilient jaws cooperating with the outer end of at least one of said strips of each contact arm for holding said fuse link to interconnecting position therebetween, each of said jaws comprising a strip of resilient material with the long dimension of its transverse section substantially vertical, and spring means for biasing said lower contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

13. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted on the upper end of said insulator and electrically connected to said transmission line terminal, another transmission line terminal mounted adjacent the lower end of the insulator, a rigid contact arm including pivot means extending through said skirt of the insulator into said recess and electrically connected to said other transmission line terminal, said pivot means extending transversely to the longitudinal axis of the insulator, said pivot means also being fixedly connected to the second said contact arm externally of the skirt of the insulator, a fuse link interconnecting said contact arms, and spring means within said recess of the insulator for protection against weather and for urging said pivot means to rotate the second said contact arm away from the first said fixedly mounted rigid contact arm and thus tension. said fuse link.

14. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted on the upper end. of said insulator and electrically connected to said transmission line terminal, another transmission line terminal mounted adjacent the lower end of the insulator, a lower rigid contact arm including a pivot pin extending through alined openings in the Wall of said skirt and through said recess in the insulator bottom end, said lower rigid contact arm being electrically connected to said other transmission line terminal, said pivot pin extending transversely to the longitudinal axis of the insulator and being fixedly connected to the second said contact arm externally of the skirt, a fuse link interconnecting said contact arms externally of said insulator, and spring means within said recess of theinsulator for protection against weather and for urging said pivot pin to rotate the lower contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

15. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and being reentrant at the base, thus providing a recess therein, a transmission line terminal mounted adjacent the upper end of the insulator, an upper contact arm fixedly mounted adjacent one end thereof on the upper end of said insulator and electrically connected to said transmission line terminal, said upper contact arm having the other free end thereof projecting substantially laterally away from, the insulator, another transmission line terminal mounted adjacent the lower end of the insulator, a lower contact arm having one end thereof pivotally mounted at the lower end of said insulator and electrically connected to said other transmission line terminal, the other free end of the lower contact arm projecting substantially laterally of the insulator at least in the closed circuit position of the device, the free ends of the two contact arms being spaced from each other, a fuse link interconnecting the free ends of the spaced contact arms, and spring means within the recess of said insulator for protection against weather and for biasing said pivotally mounted contact arm away from said fixedly mounted contact arm to tension said fuse link.

16. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted adjacent one end thereof on the upper end of said insulator and electrically connected to said transmission line terminal, the other free end of said rigid contact arm projecting substantially laterally from the longitudinal axis of the insulator, another transmission line terminal mounted adjacent the lower end of the insulator, a rigid contact arm including pivotmeans extending through said skirt of the insulator into said recess and electrically connected to said other transmission line terminal, the outer free end of the second said contact arm projecting substantially laterally from the longitudinal axis of the insulator at least in the closed circuit position of the device, the free end of the second said contact arm being spaced from the free end of the first said contact arm, a fuse link interconnecting the spaced free ends of said Contact arms, and spring means within said recess of the insulator for protection against weather and for urging said pivot means to rotate the second said contact arm away from the first said fixedly mounted rigid contact arm and thus tension said fuse link.

17. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted adjacent one end thereof on the upper end of said insulator and electrically connected to said transmission line terminal, the outer free end of the rigid contact arm projecting substantially laterally away from the longitudinal axis of the insulator, another transmission line terminal mounted adjacent the lower end of the insulator, a lower rigid contact arm including a pivot pin adjacent one end thereof extending through alined openings in the wall of said skirt and through said recess in the insulator bottom end, said lower rigid contact arm being electrically connected to said other transmission line terminal, the outer free end of the second said contact arm projecting substantially laterally of the longitudinal axis of the insulator, at least in the closed circuit posi tion of the device and spaced from the outer free endof the first said rigid contact arm, a fuse link interconnecting the spaced free ends of said contact arms externally of said insulator, and spring means within said recess of the insulator for protection against weather and for urging said pivot pin to rotate the lower contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

13. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and having a skirt giving a recess in the underneath side of the insulator bottom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted adjacent one end thereof on the upper end of said insulator and electrically connected to said transmission line terminal, the other free end of said rigid contact arm projecting substantially laterally from the longitudinal axis of the insulator, another transmission line terminal mounted adjacent the lower end of the insulator, a rigid contact arm including pivot means disposed adjacent one end thereof extending through said skirt of the insulator into said recess and electrically connected to said other transmission line terminal, the other free end of the second said contact arm projecting substantially laterally away from the longitudinal axis of the insulator at least in the closed circuit position of the device, and spaced from the free end of the first said rigid contact arm, said pivot means extending transversely to the longitudinal axis of the insulator and being fixedly connected to the said one end of the second said contact arm externally of the skirt, a fuse link interconnecting the spaced free ends of said contact arms, and spring means within said recess of the insulator for protection against weather and for urging said pivot means to rotate the second said contact arm away from the first said fixedly mounted rigid contact arm and thus tension said fuse link.

19. A fuse cutout for outdoor use comprising, an electrical insulator suited for mounting in an upright position and havin a skirt giving a recess in the underneath side of the insulator bottom end, a transmission line terminal mounted adjacent the upper end of the insulator, a rigid contact arm fixedly mounted adjacent one end thereof on the upper end of said insulator and electrically connected to said transmission line terminal, the other free end of said rigid contact arm projecting laterally away from the longitudinal axis of the insulator, another transmission line terminal mounted adjacent the lower end of the insulator, a lower rigid contact arm including a pivot pin adjacent one end thereof extending through alined openings in the wall of said skirt and through said recess in the insulator bottom end, said lower rigid contact arm being electrically connected to said other transmission line terminal, the other outer free end of the second said contact arm extending laterally away from the longitudinal axis of the insulator at least in the closed circuit position of the device and spaced away from the free end of the first said contact arm, said pivot pin extending transversely to the longitudinal axis of the insulator and fixedly connected to the said one end of the second said contact arm externally of the skirt, a fuse link interconnectin the spaced free ends of said contact arms externally of said insulator, and spring means within said recess of the insulator for protection against weather and for urging said pivot pin to rotate the lower contact arm away from said fixedly mounted contact arm and thus tension said fuse link.

JAMES M. WALLACE. EARL F. BEACH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,319,161 Schultz May 11, 1943 2,320,026 Birkenmaier May 25, 1943 2,324,044 'Iriplett et a1 July 13, 1943 2,347,851 Steinmayer et al. May 2, 1944 2,493,432 Yonkers Jan. 3, 1950 2,512,498 Linde et al June 20, 1950 

